Pressure release valve



Sept. 26, 1944. T. E. NICHOLS 2,358,875

' PRESSURE RELEASE VALVE Filed July 29, 1941 2 Sheets-Sheet 1 Q Q N v Hr N x TAM, M'cals.

' INVENTOK BY E M/ W ATTO IE Y.

p 1944- T. E. NICHOLS PRESSURE RELEASE VALVE Filed July 29. 1941 2Sheets-Sheet 2 mm, E. Mew/ INVENTORf Patented Sept. 26, 1944 PRESSURE;RELEASE VALVE Thomas E. Nichols, Houston, Tex., assignor of one-half toScott Red, Houston, Tex.

, Application July 29-, 1941, Serial No. 404,448

Claims. (01. 158-363) This application is a continuation-in partvof mypreviously filed application, Serial No. 244,259, filed December 6,1938, for Pressure release valve.

This invention relates in general to pressure release valve and has forits general object the .provision of such a valve which may be employedin connection withthe fuel pump and carburetor;

or the like, of an internal combustion engine to prevent flooding of thecarburetor, or the like,

. after the engine has been stopped, and to prevent I wastage of fuel.

- While this invention is applicable to any situation in whichthere is afluid supply under pressure which is to be transmitted to a point of usewhere its flow is controlledby a valve, and it is desired to avoidleakage from the source of fluid under pressure past such valve duringperiods of idleness immediately following periods of use, this device isespecially adapted for use in the fuel system of an internal combustionengine such as is commonly found in an automobile. j

In the ordinary fuel supply system used in automobiles, the fuel is fedby means of a pump, or some other suitable apparatus under pressure tothe carburetor. Its flow into the carburetor is controlled by a floatactuated needle valve. Most such fuel pumps furnish fuel at a pressureof several pounds per square inch more than is actually required to feedthe fuel to the carburetor. Upon investigation of many cases ofautomobiles which were found to be hard to start after having been inoperation but a short time before, I have discovered that the apparentreason 1 for such diflicult starting is that the fuel under pressurebetween the pump and the needle valve of the carburetor when the engineis stopped slowly leaks past such needle valve into the carburetor,thereby providing an excessive fuel supply and resulting in what isordinarily termed flooding of the engine, which prevents it from beingreadily started. v p

It is a more specific object of this invention,

, therefore, to provide a means whereby such excessive pressure of fuelbetween the fuel pump and the needle valve of the carburetor may berelieved upon-stoppage of the engine and where-' by this may beaccomplished without the wastage of fuel. I 7

It has also been found that the immediate source of fuel into thecarburetor as a result of the starting of the engine and the opening ofthe needle valve often times causing flooding of the carburetor andcauses the engine to stop almost immediately after it has started, andthereafter- 1 prevent it from being readily started again.

It is, therefore, another specific object of this invention to provide adevice which will prevent the surge of an excessive supply of fuel intothe carburetor immediately after the engine ,has started.

Other objects and advantagesof this invention will become apparent fromthe following description taken in, connection with the accompanyingdrawings in which isillustrated one embodiment of this invention.

In the drawings: 7 V

Figure 1 is fragmentary side elevation of a device constructed inaccordance with this invention shown in theposition it occupies withrespect tothe fuel pump and carburetor of an internal combustionenginesuch as is commonly used in an automobile.

Figure 2 shows a longitudinal cross-section through the valveillustrated in Figure 1. I

Figure 3 shows t a transverse cross-section through the same valve takenalong the line 3-3 of Figure 2. 7 I

Figure 4 is a view similar to Figure 3, but taken along the line 44 ofFigure 2. I

In Figure 1 there is, shown diagrammatically an engine I which may bethe usual type of internal combustion engine employed in automobiles.The intake manifold of this engine is shown at 2 and the carburetor: isshown at 3 for supplying a proper fuel mixture to the manifold Th fuelis intended to be supplied to the carburetor by means of afuel pump 4,connected in the usual of the carburetor is customarily located achamber having a float therein which controls the needle valve, closingthe valve when the float rises and opening the valve when the floatfalls.

This serves to control the entry of fuel into the carburetor through theopening I.

' The device'o'f this invention is connected to the pump 4 by means of apipe 8 and to the intake'openingl of the carburetor by means of l2 whichis connected to the pipe 8 and the outanother pipe 9. It consists of amain body 'por tion In covered by a cover member H and having aninternal structure such as will be presentlydescribed. In addition tothe intake port structure of the device, as illustrated inFigures piston2 I I this piston-being hollow for portion ofits length. butbeing-closeda -end-as shown 'at- 22. --Preier-ably,- this piston is The. piston 'isrelatively close ing to prevent lea and number as the openings 20. *On'its outer municates directly with the lower end portion of the cylinderI8 .so that .f uel entering through the port I2 is discharged "directlyinto cylinder i8 10 at its lower end.

Adjacent its upper end the wall I1 is provided with a plurality ofspaced radial openings 20 providing communication between the interiorof the cylinder I8 and the annuIarspaceIB surrounding this cylinder. Thecover member II may or may not close the upper end of the cylinder I8,this being immaterial to theoperation of the device. The only essentialfunction of this cover member is to close the upper end of memher I0.

The outlet port I3-communicates directlywith the-annular spaceor chamberI Swithinthe member '-I 0 at a point spaced -somewhat-below the openings20, but a considerable distance above ---the lower end: ofmember I I I].

- The opening I4 which is provided .for the rel-iefof. pressure, aswillbe;-presently: described, extends through the annular space I 9.tocommunicate with the interior of-=the cylinder-I8 only ata pointintermediatezthe-ends of this cylinder.

Slidablymounted-within the cylinder I8 is a the major t its upper v madewith relatively thiokwallsso as to provide it with a substantial amount-of weight, -the amount ofweight provided however being de--pendentupon-"the pressure "which is ordinarily- 4o provided by thepump, it beingobviousthat the weight of the piston should not be greatenough to-interfere with the normal operation of- -the pump. Also, theopening through the piston -must, of course; be 'sufficiently' large sothat it will be able'toallowifree passage of sufficientiuel tosupplythe-carburetor under all conditions.

fitted within'the cylinder awith a fit, but isnot provided with pack--kage about the piston.- For t'his reason, there may be a small amountof leakage past the piston at alltimes where there is sufiicientdifierential 'pressure at two points on the i length of the piston tocause le'akage.

' Adjacentits upper end,'the piston is provided with a plurality ofspacedradial openings 23 providing communication between the hollowinterior of the piston and the exterior of the piston, and theseopenings are so positioned that when the piston is i cylinder I8, theseopenings 'Wi1l' on the same level as the opening 20 and the openn its"uppermost position withinthe be substantially ings 23 are made; ofsubstantially the same size ing the various openings-23. Ihis isfor thepurg thatwhenever the piston is in its ition there will be communicationpose of insurin uppermost pos between thehollowinterior of the pistonandtheoannular space 19 through the-openings-20 and 23 and the channelor-groove 24.

Intermediate its ends and belowthe openings --23- the piston is-providedwith anotherv passage or opening :ZS proViding communication betweenits.

hollow interior and its exterior. There is also a circumferential groovein the exterior surface of the piston as shown at 26 on the same levelas the opening 25. This groove and opening are so positioned that whenthe piston is in its uppermost position they will lie a substantialdistance above the relief port I4, but when the piston has moveddownwardly a substantial distance and ..the groove 24.; and theopenings. 20 .no longer register, the. groove 26 and the relief port I4will come into register, thus providing communication between theinterior of the cylinder I8 and the piston 2I, and the relief port I4.

In operation, when the engine to which a device, .of .this ,kind isconnected, is started, the pump will start; operating and will cause abuild up of pressure below and within the piston 2|. -This- Will --tendto raise the piston M and this piston will move towards the top of thecylinder I8. As above stated, the upper end of the cylainder I 8..may.ormaynot be completelyclosed by .thecover iI I1If.=it.beassumedthatthe.upper'end .:.of the cylinder. :I 8.- is.closed: .by the mover; I. I then as. soon as the. upper; end :of.thaipiston. 2 I. closes the .port 20,- further .upward lmovementaohthepiston will be. accomplished as.leakage. takes place from above thepiston. down-v around the piston and into the-portsiZlI.lnaiveryfewqseconds the piston-wi1l riseluntilthe ports 20and 23register, whereupon fuel .will .flowthrough those ports. in whateveramounts may be required. During: this time before the ports registerthe-engine .may operate on =the..-fue1:-inthe carburetor-bowl. =At alltimes while the pump is running-there is, of course; aminute leakagepast the piston-intothe port- I4 and thence back through the by-pass I 5to-the pump'intake 4. Thisle'akage, however, -isso--sma1las to .beinconsequential during -the --operation of the engine.

' If-it be assumed-that the upper end of the cylinder I8 is-not closedby cover -I I-, theoperation would be--the-'same except thatthe pistoncould move completely to the --upper -end=of its travel withoutnecessity for-leakage. A In' the event-the=engine should stop or' beshut--offand the needle -val-ve admitting fuel to the engine shouldfor'thatreason,-or-any other-reason; be -closed-there will remain withincylinder l 8,the piston --2 I the chamben -I9',-and' -the l-ine "-9,--aquantity opium-under pressure. However, '-when the-engine is shutoff-and stops as-it would beif the needle valve were closedforanyreason, the pumpwill also stop.

T-hepresent invention has" forits purpose the provision of ameansivhereby under-those-circumstances the pressure existingwithin'thespace indicated. when the-"motor stops-lw-ill --be bled' offand by-passedbackto the. fuel supply so that it a will-not-becaused toleak past the' needle :valve into the carburetor, and cause-flooding--of the carburetor or wastage of fuel.

The device doesnot operate-"-to---relieve the .said...pressureinstantaneously -when .the :motor stops. :However, when the motorstops-ithepressure in the chamber I 9 and tl-i'at-w-ithin' thecylinderI8 -being substantially-aequal; the piston ..will begin to move:downwardly under itsown weight as rapidly as leakage can take placefrom the upper edges of the port -23 upwardlyinto and through port 20.This leakage in itselfi w-ill of -course, not relieve thelpressure"either within the cylinder- I 8-orthechamber- I 9; but there may be someleakage; past J the piston into i the i port icI-fl which will somewhatrelieve the pressure within these spaces :during this time. As soon as'the and'within the chamber I9 will be immediately *relieved as asubstantial quantity of the fluid flowsv out through port I4 and as thepiston 23 drops in consequence of such flow. This relieves the pressureon the needle valve of the carburetor so that as, the motor stands idlethere will not be a leakage past this needle valve to flood thecarburetor or to waste fuel. Instead, the pressure is relieved bybleeding the fuel back to the fuel supply and when it is again desiredto start the motor, it will be found to be in perfect condition forstarting with no flooded condition existing.

When the motor is again started, there will be a relatively small amountof fuel remaining within the carburetor bowl so that the motor may rununtil the piston 2| is forced upwardly to the point where the ports 20and 23 come into communication with each other. The fuel in the chamberl9 below the ports 20 may be forced by the pressure of the rising pistonto flow slowly into the carburetor during this period, but there cannotbe an excessive surge of fuel into the carburetor, such as would causeflooding thereof.

In view of the foregoing, it will be appreciated that a means' has beenprovided for carrying out all of the objects and advantages sought bythis invention.

Having described my invention, I claim:

1. In a device of the character described, a carburetor having a floatoperated needle valve therein for controlling the flow of fuel into saidcarburetor, a pump for supplying fuel under pressure to said carburetor,a body having a valve chamber therein connected at one point to theoutlet of said pump to receive fuel under pressure'therefrom and atanother point to the needle valve of said carburetor to supply fuelunder pressure thereto, said chamber having a pressure relief porttherein connected to the intake of said pump for relieving excessivepressure of fuel between said pump and said carburetor needle valve whensaid valve closes, and means in said chamber in the path of fluid underpressure flowing through said chamber from said pump to said needlevalve and freely movable thereby toward the connection with said needlevalve to a position covering said relief port to maintain said reliefport closed, and said means being freely retractable away from theconnection with said needle valve when no fluid is flowing through saidchamber to open said relief port and relieve pressure of fluidthroughout said chamber and on said needle valve.

2. A pressure release valve comprising a casing having a fluid outletchamber adapted to be connected to a device utilizing fluid underpressure, said casing having an inlet fluid chamber adapted to beconnected to a fluid pressure pump, said casinghaving ports tocommunicate said chambers, a piston type valve operating in the inletfluid chamber between the inlet of the inlet fluid chamber and saidcommunicating ports and movable toward said ports under the fluidpressure.

from the pump and having a groove having ports to register with theports of the casing to open r 3. In combination with a pump and thecarburetor of an engine, a presvalve when said valve moves away fromsaid communicating ports.

fluid fuel pressure sure release valve comprising a casing having afluid outlet chamber adapted to be connected to a float chamber of thecarburetor, said casing havingian "inlet. fluid chamber adapted to beconnected to the fluid fuel pressure pump, said casing having ports tocommunicate said inlet and outlet chambers, a piston-type valve movablein the direction of "fluid flow in the inlet fluid chamber under fluidpressure from the pump and having an outside annular groove thereinhaving ports to register with the ports of the casing to open thechambers to each other upon such movement, a by-pass pipe connected tothe fluid receiving side of the pump, said casing having a passage fromsaid inlet chamber with the by-pass pipe connected thereto, said pistontype valve having a part substantially closing said passage when saidvalve is in a position to open said inlet and outlet chambers to eachother, and having a port movable to register with and open said passageupon cessation of fluid flow into said inlet chamber to permitby-passing of fluid from the fluid inlet chamber back to the receivingside of the pump.

4. In combination with a pressure fuel supply and the carburetor of anengine, a pressure release valve for fuel systems of internal combustionengines comprising a vertically arranged cylinder having an intake portin the lower end therepf and adapted for connection to the pressure fuelsupply, a chamber arranged about said cylinder and having a portadjacent the upper end thereof and adapted for connection to thecarburetor, said cylinder having ports adjacent the upper end thereof tocommunicate the cylinder with said chamber, a bypass means connected tosaid cylinder below the ports of said cylinder and adapted to beconnected to the fuel supply, and a gravity influenced piston-type valveslidable in the cylinder and movable in the direction of flow by thedifferential between the pressure of the fuel supply and the pressure offuel in said chamber to open the ports of said cylinder and to close thebypass means so as to permit fuel to flow to the carburetor, and movableby gravity to automatically. close the ports of said cylinder and opensaid bypass means when the flow of fuel to the carburetor is stopped bythe closing of a fuel float chamber thereof causing a back pressure offuel in said fuel chamber which equals the pressure of fuel from thefuel supply.

5. A pressure release valve for fuel system; of

internal combustion engines comprising a vertically arranged cylinderhaving a fuel inlet port in the lower end thereof adapted for connectionto a pressure fuel source, a chamber formed on said cylinder andsurrounding the vertical walls of the cylinder and having a port adaptedfor connection to a carburetor of an engine, said cylinder having portsadjacent the upper end thereof to connect the chamber therewith, saidcylinder having a bypass passage located substantially intermediate theends thereof and extending through the chamber with noncommunicationtherewith and adapted to be connected to the fuel source for the returnof fuel thereto, and a piston slidable in said cylinder between saidfuel inlet port and the ports adjacent the upper end of the cylinder andsaid piston being influenced by gravity, and having .:ports adjacent theupper Vendrothezeof, and said piston being movable underizdifienentialinf :pressure between :said ivcylinder ;and said :ohambe!"1130 align the :ports ;of "the :pistonvmith :;the

morts adjacent the zupper aend. of the icylinder,

,whenthere is a-flow .dfzfuelzfromithessource 50f athe carburetorandsaidpiston aheing adapted :to be moved :by :gravity i170 .imoveiahe pontsndf:the piston out of -:alignmentwith :.the ;ports eof gamma 5:; ing ,amortzto align with the bypass ,passage when said :piston lowers :toclose the ports .of said :cyi- 1inder; -and thereby permit return :ofthe :fuel ,to theisoureeefitom "the cylinder.

THOMAS E; FNICHOIJIS.

